


Unexpected

by Aurorealis



Category: The Avengers - All Fandoms
Genre: Animal Transformation, M/M, Transformation
Language: English
Status: In-Progress
Published: 2012-08-30
Updated: 2012-09-02
Packaged: 2017-11-13 05:32:18
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 4,009
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/500036
Author URL: https://archiveofourown.org/users/Aurorealis/pseuds/Aurorealis
Summary: <blockquote class="userstuff">
              <p>Prompt fill on avengerkink. An experimental weapon turns the Hulk into a giant half fish monster, and by extension, Bruce turns into a merman. He and Tony are the only ones smart enough to figure out how to turn him back, but how is Bruce supposed to help when his hands are webbed and he starts to dry up when out of water for too long? Tony's not much help either, as intent as he is on making the best of this chance to poke fun.</p>
            </blockquote>





	1. chapter one

The last thing Bruce properly remembers is the normal rush before a battle. The alarm pounding through his ears, punching into his carefully maintained control, but not enough to set off the other guy. The scrambling up from the lab, up onto the roof and into the jet. The stomach flipping turning and swerving from the jet avoiding enemy fire. The jet door opening, Thor and Tony streaking out first, followed quickly by Clint, Natasha, Steve, and himself. The brief glance at the widespread damage already caused by the villains. He even had time to realize that this time the enemies were holing up in a building, probably hoping to funnel the Avengers through the single entrance and pick them off one by one. They should know by now that nearly all of the Avengers could create their own entrances anyways.

Then the other guy, or as everyone liked to call, the Hulk takes over and everything turns green. His consciousness is left on its own for a while, to hope that the other guy won't hurt anyone who wasn't a bad guy this time.

Well, Bruce actually can remember a bit more, if he concentrates. Everything is fragmented and muddled when the other guy is out. But if something significant happens, he can sometimes get a better idea. Looking down at himself, Bruce concedes that if this isn't significant, he didn't know what else could. 

There's the feeling of machinery being crushed underfoot and between his hands, the sound of screaming that the other guy hates so much. Those bits are usual. 

Then there's a slightly more lucid memory, where Bruce feels a surge of protectiveness from the Hulk. The ground- cement dusted with debris from the smashed walls of the building- scrape under him and wind whistles past him. Hulk rushing forward, metal man is hurt. Have to rescue metal man! 

Bruce blinks at the memory of the Hulk's clipped thoughts. The other guy didn't usually think, at least not strongly enough that Bruce can sense it. And even as the panic that Tony is injured, and needs to be saved, rushes through him, Bruce reminds himself that Tony is right there. He's fine and honestly, Bruce is probably in a worse position. He forces himself to continue his attempts at recollection.

There's some relief now, metal man safe. There's a flash of red and gold up above, Tony flying safely in the air again, firing blasts at a strange machine. Hulk saved metal man, let him take care of himself. Metal man strong. A few more fragmented sensations flit by, a metal plate folding like paper under his hand, the tiny pinch that was a bullet uselessly pinging off his side. 

Finally, something unusual. Bright light, something that Bruce hates almost as much as the other guy. Pain, something Bruce never felt from time as the Hulk, beyond the slight soreness caused by the transformation. He feels his bones, already giant and misshapen, shifting, sliding. Flesh bubbling and sliding and joining together, being weighed down as more built up on an already over grown frame. The ache of his vocal cord as the Hulk roared and screamed. Heat and explosions as Hulk thrashes and twists, his legs trapped together by something. A piercing pain- something could cut the Hulk like that?- crawling down his arms and up his back, across his neck. Sputtering, choking, confusion, he can't figure out how to breathe and then a deep breath. 

Now there are voices, pleading voices. “-t's over, done!” “-ed to let Bruce ba-” “-ome on, big gu-” The only one that Bruce fully hears through the other guy's ears is Tony. “Hulk, Bruce can help fix you better than just I can! You need his genius now, like he needs your smashing!” He feels the other guy's uncharacteristic panic and anxiety. There's no way they talked reason into a panicking Hulk! And yet, Bruce now clearly remembers a single thought, you help now, just before the haze of green recedes, and Bruce finds himself in this position.

Bruce looks down at himself again. His entire body, save for his head, the front of his neck, and the front of his torso is covered with shimmering green scales. The scales are a dark green, with a pattern of lighter green stripes that seem to match the other guy's eyes. Bruce flexes his fingers apart, fingers that are now webbed. The palms of his hands are another part that have been spared from scales, as well has the underside of his forearms. Sprouting out of his arms, from the smallest fingers all the way to his elbows, are large pale green fins- one for each arm. With a muscle that Bruce assumes is new, the fins fold tightly against the scales. He can also tell that there is a similar fin on his back.

Bruce doesn't need to see to know that something has changed his neck as well. It feels like an open cut, except that the pain is gone. Going by the theme so far, Bruce assumes that they are gills. He doesn't want to think too much on it.

None of those things are anything compared to the biggest change at all, the one that Bruce first noticed and had caused him to think back on how and when, exactly, this had happened. He didn't have legs anymore. The supposed binding of his legs that Hulk had felt, was actually them fusing into a single limb. 

Bruce's legs are a tail. Despairingly, Bruce realizes that they were extremely reminiscent of a mermaid's tail. Starting as thick as his torso, slimming down until it was about as thick as one of his ankles, and ending in a great big fin. The tail is very long- longer than Bruce's normal legs. It's all very streamlined and surprisingly, his still human parts and these strange new fish parts seem to blend perfectly. Whatever was done, Bruce could still breathe, think, and speak. Which is what he did, as he looked up into the faces of his shell shocked friends. It seemed that they were waiting for him to say something first.

“ My body appears to have mutated in an unexpected, drastic way. I believe that is has something to do with the experimental weapon that the enemies were originally threatening us with. Am I correct in saying that the other guy was hit by the weapon?” 

There were various nods and mumblings of assent. Steve looks like he's about ready to faint from shock. 

“Well then.”, Bruce began in his calmest, most sensible voice. “We should bring the weapon back with us, then. And perhaps we should get to the tower as soon as possible, I don't think the media seeing this would be a good idea.”

That got the other Avengers scrambling. Natasha tuned her comm link to whoever was flying the jet- letting him know that they are ready for pick up. Steve and Clint go to the crushed remains of the weapon- a great big machine built into the floor with a giant, but snapped off, barrel. Thor follows, helping Steve rip the machine from the bolts that secured it to the ground. 

Tony, instead, quietly walks up, sitting beside Bruce. He can hear the suit's quiet mechanical whirring. 

“Well... this is a little different.” Tony begins casually. 

“I would consider that an understatement.” Bruce replies, equally as easy. He supposes that he should be freaking out, and indeed the scientific part of him is running over all of the reasons that this wasn't possible. The logical part of him can at least remind himself that the other guy was just as impossible as this is. In fact, being a strange merman thing was not nearly as bad as the other guy. Logically, he shouldn't worry until after he goes through some detailed analysis. After all, it could easily be something that wears off or is easily reversed. Bruce doesn't think that the rest of himself- the part that was neither scientific nor logical, the normal part- is caught up yet. 

Bruce is brought out from his musings by Tony, who's sliding a hand across Bruce's scaled hip. “On the upside, your scales are so, so pretty.” Bruce swipes his hand off with an annoyed expression. “Be serious, Tony. I have scales everywhere, fins on my arms and back, and my legs are a tail. Prettiness is not exactly an upside.”

“But I am serious”, Tony pouts, “You make the best mermaid ever! The Hulk makes the second best mermaid. You should have seen the damage he did with that tail.” Bruce sighs and puts a webbed hand over his forehead. 

“Oh, you know you love me.” Tony teases, slinging an arm around Bruce's scaly shoulders. Despite his outward exasperation, Bruce leans into his partner, ignoring the cold metal of his suit. 

“Yeah, I guess”, Bruce admits quietly. His mind is exploding with theories and ideas and concerns on this mutation to his body, while the Avengers were each freaking out in their own way, being very obvious with their concern and shock. Amidst all of this, at least somebody isn't taking it seriously.


	2. Chapter 2

**Summary for the Chapter:**

> In which Bruce finds out that he is now an aquatic creature in more than just shape.

The ride back to the tower is surprisingly uneventful. Tony lifts Bruce up by the shoulders, and Steve awkwardly takes his tail. Bruce shoots Steve an apologetic look, the man had enough to deal with the 21st century, never mind a team mate morphing into a half fish. Between those two, Bruce finds himself wedged into a seat, tail flopped across the middle of the floor, long as it is. He's sure that the pilot has seen him, and has just decided not to even bother wondering. Bruce would have given up trying to understand it too, if he wasn't actually experiencing it. 

The ride seems much longer than it is. First, there's the dull throbbing headache, making even simple thought process difficult. Then the room starts to tilt and swat sickeningly, only this time the jet isn't rushing to dodge enemy fire. Bruce gulps, trying to wipe off sweat that isn't there. Everything is so dry, and now his skin is aching, begging for relief. But for what relief? What is wrong? Is the weapon killing him now? Mutating his body to this form that it can't handle, and he's going to die here of who-knows-what? 

“Hey, Brucey, you okay? Besides the obvious?” Tony's red gloved hand waves in front of his head. 

“I'm fine-”, Bruce begins, before cutting himself off. This couldn't be a coincidence, and while he probably wasn't going to die, it definitely had to do with the mutation. “Actually, I'm not. I've got a headache, and a fair amount of dizziness. My skin hurts too, like picking a scab. It's hard to explain.” 

After all, this being such a unique case, Bruce knows that his symptoms shouldn't be ignored just as much as they shouldn't be used as an excuse to freak out. Even if it makes Tony flip out. 

“Woah, okay, why aren't we at the tower, right now? You need to get to a doctor, or something.”

“Tony, somehow I don't think a doctor will be exactly useful in this case.” Bruce feels sick, everything is just so hard to concentrate on. “Can you explain anything else?” Tony prods with worry. 

“I... everything just feels dry, like I'm dehydrated or something, but I know I'm not..” As soon as the words come out of his mouth, Bruce groans.

“You don't suppose..” He trails off, not wanting to finish the thought as the jet finally lands on the roof of the tower. 

“Well, you are part fish now. I guess you just need some water to swim in!” Tony grins, and Bruce can't tell if it's relief at a possible solution, or amusement at the solution itself. Knowing him, probably both. 

“Okay, let's get our fishy friend an aquarium. I've got a pool on one of the basement floors.” He pulls at Bruce's shoulders again, leaving Steve to resume the tail position again. The other Avengers, mostly silent out of the pure strangeness of the situation, burst into life again. Thor and Clint start to bring in the machine components, while Natasha contacts SHIELD. Her job of explaining this mess to Fury was unenviable for certain. 

Awkwardly, the trio makes it to the elevators. Normally, Bruce is indifferent to Tony's extravagant lifestyle, but now he's really glad for the extra large elevators. He experiments shifting the tail appendage that now acts as a substitute for his legs. With his inexperience, it twists up and down, and his fin whips Steve in the face, who proceeds to drop Bruce's tail to the floor with a shout. 

“Uh.. Sorry about that.” Bruce apologizes, while Tony doesn't bother holding back his amusement. The headache isn't really helping his concentration, and now he's feeling faint from the movement. Steve plucks the tail back up, this time keeping watch of the bulky tail fin. 

When the doors open, everyone's eyebrows raise. “You know, if you had a pool this big, why do you always bug so much about going to the beach for vacation?” Bruce points out. Tony only shrugs. “ I think I actually forgot it was this awesome. I haven't been here since way before we met. But I guess we'll be using it more now.” Steve only stares for a moment, than shakes his head and leads the way. 

There are several pools. One of them is huge and rectangular, built to swim laps. Another one looks to be more for leisure, it is just as big, but with rocks, ledges, and a round, casual shape. The third is significantly smaller, but still plenty big enough for twenty people to mill about in. It seems to be a hot tub. 

“Now, let's just hope you're freshwater. I remember the pool uses salt for the chlorine, but it's really not strong enough to be salt water.” Tony announces. “Yes, let's hope.” Bruce agrees.

Without much thought, they go towards the leisure pool. Steve gently sets his tail down on the pool edge. Bruce slides his fin and part of his tail into the cool water, scooting his bottom closer. Already, some of the prickling in his skin ceases, though the headache and dizziness remains. He glares at the water, feeling silly, but knowing that in all likelihood, this was the best course of action to take. “Here goes”, Bruce mutters, pushing off from the edge and submerging. 

His eyes snap open underwater. It's like a whole different world. Relief sweeps through his body. A cool feeling pricks at his neck, and suddenly Bruce doesn't need to hold his breath. Instinctively, the fins at his arms unfold. He can see their use now- as a stabilizer and as a control during swimming. Bruce twists onto his back and sinks slowly to the floor of the pool in pure bliss. Nothing had ever felt as good as this does now, Bruce was convinced. The water was amazing, already he is no longer dizzy, and the head ache is slight. 

But then Tony and Steve are looking over the edge of the pool with concern. The water is clear, and his eyes can penetrate the surface perfectly. Oh yes, Bruce realizes, they might not know about being able to breathe underwater. Almost reluctantly, he pushes up and breaks the surface with a splash.

“How is it?” Steve tentatively asks. “It's actually... just what I needed, apparently. All of my symptoms are fading or gone, and it actually feels pretty great.” Steve nods, with some relief. 

“Right, so, I'm going to... go now. Unless you need me for anything?” Steve looks awkward, scratching the side of his neck and glancing away. Bruce wants to be annoyed that the captain is handling this worse than the person who was actually affected. But that's not true, Steve is doing all he can and Bruce can hardly complain that he finds it all a little overwhelming. So instead of actually being annoyed, Bruce nods and offers a “Thanks, Steve.” Steve smiles slightly, replying “Yeah, no problem”, before practically fleeing the room.

As soon as Steve is gone, Tony suddenly squats down to Bruce's level. 

“Are those gills?” He points to the lines on his neck, but doesn't poke thankfully. “Yes, I believe so. I can definitely feel myself breath underwater in some fashion, anyway.”

“Hah. I'm calling you gills now.” Tony jokes. He looks at the water like he wants to get in too, but he's still in the iron man suit. He reaches forward to poke one of Bruce's scales. “Can these come off easily?”

“Why do you want one?” At the same time, Bruce runs a hand down his arm, feeling for a loose scale. The sensation of touch through his scales is unusual, but not unwelcome.

“Well, you DO want out of that at some point, don't you? I need a sample to look at.” Tony pointed out.

“Tony, you hate anything remotely to do with biology. You suck at it.” At this, he sticks his tongue out. “Well, you're not exactly in that field either.” 

“Yes, but I have studied it more than you have. Had to, in order to understand the other guy better. This is bound to have some similarities.” After all, there can only be so many ways to mutate the human body like this. Bruce can only hope that the change isn't permanent, like the last one was.

“Well, I don't exactly see you being in the position to do much analyzing. As the only other one of us smart enough to do anything helpful, I'm willing to make a few sacrifices.” This time, Tony does poke Bruce, prodding his cheek which is thankfully unchanged from the mutation.

“Tony, my mind is still here. I can help, and I'm better at this than you, anyways.”

“How do you expect to help? We need the lab for anything helpful, and you need to stay in the water.” 

“I'm sure I'll be fine now. I just needed to hydrate myself, or something like that. I can certainly deal with a headache if it means- ow!” Bruce yelps and looks down at his shoulder, the source of the sharp prick. Tony's hand is there, with a scale between his fingers. Next, he plucks a hair from Bruce's head. “That's so I can compare normal you DNA, and fishy you DNA. See, I'm not hopeless. Now, I'm going up to the lab, and you are going to stay here and not get out of the water.” He straightens up and turns on his heels. 

Suddenly, Bruce is nervous. He doesn't want to be down here all alone in this weird fish body. He's used to being alone, less so now that there's Tony in his life, but there's still years of experience. The problem is that this is different, and although Bruce can't tell why, the thought of being stuck by himself in this mer body sends a shiver of panic down his spine. 

“Don't you dare leave me down here Tony. I will crawl my way over to the lab if I have to.” Tony probably recognizes the neediness in Bruce's tone, because he stops and turns back again slightly.

“You know you're being very unhelpful in this. I can't very well work on turning you back down here.” 

“I know that. Just...” Bruce looks down at his deformed body in frustration. Instantly, an idea springs forth and Bruce looks back up again. “What if you bring the lab equipment down here? Can you do that?” 

Tony is taken aback, but then his face turns thoughtful, and Bruce knows that it's a good sign. After a few moments of contemplation, Tony strides over to one of the walls, covered by various machines and devices that Bruce doesn't bother identifying. Still in the Iron Man suit, Tony easily moves several large machines and takes a peek at something hidden behind. He backs up, nodding to himself, before turning back to Bruce.

“Actually, I believe I can. This floor can handle the lab equipment without blowing any circuits. I think I'll enlist Thor and Steve to help move stuff. Poor Steve, he's going to have to come back down here and get traumatized again.”

Bruce doesn't care that he's grinning like an idiot just because Tony isn't just abandoning him here. It will be a pain in the ass to move the many lab machines down here, and it'll be another huge pain moving them back up when he's finally fixed. Bruce would normally be more concerned about the inherent selfishness in this request, but right now he was only relieved. 

“Okay, I'm going for real now. Just to grab our resident weight lifters and get the lab stuff. I'll be back in five. Any more requests, Ariel?” Bruce can't even bring himself to be annoyed at the mermaid jab. Instead, he answers “Sure, since you asked so nicely, can you get me a shirt? And change out of the suit, you've been wearing it for over an hour.” 

The only indication that Tony hears him is a thumbs up as he turns away once more, disappearing behind elevator doors. Bruce pushes off from the side of the pool he had been leaning on with a sigh. He is uncomfortable again, but not in despair. Tony will be back at least, and Bruce won't have to feel like an even bigger freak than usual. 

But since no one is here currently, Bruce decides that he may as well test this body out a little. There would be plenty of time to scan and study it in a scientific manner. His whole shape is rather streamlined now, and Bruce notes that, although he has fish gills, scales, and fins, his lower half resembles a dolphin more than anything else. Probably, his swimming speed should be much faster in this form.

The problem is that Bruce was never much of a swimmer. He could tread water, and do a basic front stroke, but nothing beyond that. He certainly never learned any kind of swimming movement that could help him with two legs fused into one. Bruce ducks under the water for good measure, just in case being under the water might help instinct-wise. Plus it really did feel much better using his gills for whatever reason.

First, Bruce tries paddling with his hands. It's somewhat successful- the webbing really helps, but with his tail hanging limp, he's slowed down significantly and probably isn't any faster than he would be as a human. Stretching out the fins on his arms isn't helpful at all, and actually drags at the water, slowing him down further. Like Bruce initially thought, they seemed to be for control and stability during fast underwater movement.

Hesitantly, Bruce pumps his tail up and down, because that seems to be the proper movement. It all feels rather awkward, what with him being used to two lower limbs. It's working a little, but in no time at all, Bruce is curled up somehow and facing the bottom of the pool. He can't tell if it's because he holds his tail too straight, or not straight enough. Bruce decides that it's extremely good that he can breathe underwater in this form, or he would certainly drown.

He tries a few more times to figure out how to swim properly, and even manages to develop a method of moving forward using only his tail, although the movement probably resembles a dying sea creature more than anything else. Still, he seems to be getting a hang of it, which is good. Bruce quickens his pace as he gains more confidence, only to bash his face into the bottom of the pool as he misjudges the angle of one powerful stroke.

Rubbing his nose ruefully, Bruce decides to stick to easier challenges. Treading water sounds significantly less painful right now.


End file.
